CN106575550B

CN106575550B - Shielded electric wire

Info

Publication number: CN106575550B
Application number: CN201580042618.7A
Authority: CN
Inventors: 浦下清贵; 川上齐德
Original assignee: Tuo Da Wire Co Ltd
Current assignee: Tuo Da Wire Co Ltd
Priority date: 2014-08-12
Filing date: 2015-08-07
Publication date: 2020-01-21
Anticipated expiration: 2035-08-07
Also published as: WO2016024544A1; JP2016040760A; CN106575550A; JP6338967B2; US20170231125A1; US9918417B2

Abstract

The invention provides a shielded electric wire (P) capable of easily performing end processing. The shielded electric wire is configured to include: the conductive wire comprises eight twisted insulating core wires (1), an interposed object (2) between the insulating core wires, a pressure tape (3) transversely wound around the outer periphery of a core composed of the insulating core wires and the interposed object, a drain wire (4) arranged on the outer surface of the pressure tape, a conductive fiber braid (5) formed on the outer peripheral surface of the pressure tape by sandwiching the drain wire, a sheath (6) forming the outer peripheral surface of the braid, and an adhesive layer (7) between the braid and the sheath. When the wire is terminated, a cut t is formed over the entire outer periphery of the sheath with scissors or the like, and the terminal sheath 6' is peeled off through the cut t, the braid 5' is integrated with the sheath 6' by adhesion of the adhesive layer, and thus can be peeled off together with the sheath. Therefore, the operation of removing the braided body after peeling off the jacket is not required, and the operability of the end processing is good.

Description

Shielded electric wire

Technical Field

The present invention relates to a shielded electric wire having a shielding layer (shielding layer) against electromagnetic waves.

Background

As such a shielded wire, there are the following configurations (patent documents 1 and 2): a plurality of insulated core wires are twisted as a core, a conductive fiber braid is formed on the outer periphery of the core, and a sheath (cover) is provided on the outer side of the conductive fiber braid, the braid is braided with copper-plated polyester fibers (patent document 1) or carbon fibers (patent document 2), and the sheath is provided by extrusion molding of a resin such as polyvinyl chloride (patent document 1).

Further, there is a shielded twisted pair cable in which the outer periphery of a core formed by twisting insulating core wires is covered with a conductive foil such as an aluminum foil, and the conductive foil is adhered to a cover insulator (jacket) via an adhesive layer (patent document 3).

In these shielded wires, the end processing at the time of connection to an electronic device or the like is performed so that a sheath, a braid, or a conductive foil having a desired length is removed from the end to expose an insulated core wire. In this case, as described above, in the electric wire in which the braid is made of carbon fiber or the like and the sheath is made of an extruded product of a resin such as polyvinyl chloride or the like, since both are generally not adhered (not integrated), it is necessary to peel off the exposed braid with scissors or wire stripper and then expose the core of the twisted insulated core wire.

On the other hand, in a cable in which the conductive foil and the cover insulator are adhered to each other via the adhesive layer, the conductive foil can be peeled off while adhering to the cover insulating layer when peeling the cover insulator (see paragraph 0018 of patent document 3).

Patent document 1: japanese laid-open patent application No. 2002-175729

Patent document 2: japanese Kohyo publication No. 2002-538581

Patent document 3: japanese patent laid-open No. 2008-287948

Patent document 4: japanese Kokai publication Hei-5-38719

As described above, in the conventional braided shield wire, since the end of the sheath is processed, after the end of the sheath is peeled off by a desired length, an operation of further peeling off the exposed braid from the core of the twisted insulated core wire is performed, and the braid is braided, the operation is troublesome.

On the other hand, in the cable in which the conductive foil is adhered to the cover insulator via the adhesive layer, the conductive foil is used for the shield layer, and therefore, the bending resistance and the electromagnetic shielding property are inferior to those in the case of using the braid.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a shielded wire using a braid, which has the same degree of bending resistance and electromagnetic shielding characteristics as those of conventional shielded wires, and which can be easily subjected to terminal processing as compared with conventional shielded wires.

In order to achieve the above object, the present invention provides a shielded electric wire using a braid, wherein the braid can be removed while the sheath is peeled off.

Specifically, an adhesive layer is interposed between the conductive fiber woven body and the sheath, and the conductive fiber woven body is adhered to the sheath by the adhesive layer.

In this way, when the sheath is peeled off, most of the (integrated) knitted fabric adhered to the sheath is also peeled off at the same time, and therefore, the operation of removing the knitted fabric can be omitted. Therefore, the end processing becomes easy as compared with the prior art.

Further, since the conductive fiber woven body is provided with the adhesive layer on the surface thereof and is adhered to the sheath (integrated) via the adhesive layer, the structure of the woven body is less likely to collapse due to repeated bending of the electric wire, and the bending resistance and the shielding property are not reduced. Further, when a tensile force in the longitudinal direction acts on the sheath of the electric wire, in the case of a conventional shielded electric wire using a braid that is not adhered to the sheath, the tensile force is mainly concentrated on the sheath located at the outermost layer, but the shielded electric wire of the present invention integrates the sheath and the braid via an adhesive layer, and the tensile force is concentrated on the braid having a large young's modulus (difficult to stretch) and resists the tensile force, thereby improving the tensile resistance of the sheath.

In addition, when the adhesive layer is formed of a thermoplastic adhesive resin, since the sheath is usually formed by extrusion molding of the resin, the adhesive resin is melted by the heat of the resin at the time of the extrusion molding, and the two resins are firmly bonded to each other, thereby improving the bonding strength between the conductive fiber woven body and the sheath via the adhesive layer. Therefore, the above-described bending resistance and prevention of deterioration of the shielding property can be further achieved.

A shielded wire according to the present invention is a shielded wire in which a plurality of insulated core wires are twisted to form a core, a conductive fiber braid is formed on the outer periphery of the core, and a sheath is provided on the outer side of the conductive fiber braid, and the shielded wire can be configured such that: an adhesive layer is interposed between the conductive fiber woven body and the sheath, and the conductive fiber woven body is adhered to the sheath by the adhesive layer.

In this configuration, grounding can be performed by connecting the conductive fiber braid to a ground terminal or the like as in the conventional art, but a configuration may be adopted in which a drain wire is provided between the core of the twisted insulating core wire and the conductive fiber braid, and the drain wire is electrically connected to the conductive fiber braid.

As described above, when the jacket is peeled off, the knitted fabric adhered to the jacket is also peeled off at the same time, and the knitted fabric of the terminal portion corresponding to the peeled jacket may disappear entirely. In such a case, it is difficult to perform grounding (earth) using the braid of the tip portion.

However, if the drain line is separately provided between the core of the twisted insulating core wire and the braid and the operation of peeling off the sheath is performed, the drain line is not cut off (if a slit t described below is not formed in the drain line 4), and then the drain line exists (remains) at the end after peeling off the sheath and the braid. That is, in this structure, since the entire braided body may be removed by peeling off the sheath, a drain line is separately provided. In general, in a shielded wire having a conductive fiber braid, a drain line is not provided because grounding is performed by the braid.

As means for interposing the adhesive layer between the conductive fiber woven body and the sheath, various means are conceivable, but for example, the following means can be adopted: in the manufacturing process of the shielded wire, the thermoplastic adhesive resin is extruded in the moving process of the core of the conductive fiber braided body, so that the adhesive layer is formed on the whole outer circumferential surface of the conductive fiber braided body.

When the adhesive layer is formed in this manner, the adhesive layer can be smoothly formed on the entire outer peripheral surface of the knitted fabric by extrusion molding. Therefore, the braided body can be reliably peeled off while the sheath is peeled off, and further improvement of the bending resistance and prevention of reduction of the shielding property can be achieved.

When the conductive fiber woven body is made of a resin-coated fiber, the strain resistance of the fiber is improved, and the possibility of fiber breakage during the weaving process is reduced, and in a shielded wire using the woven body made of the fiber, the fiber breakage is less likely to occur when the shielded wire is repeatedly subjected to a bending action, and the bending resistance is improved. The thickness of the resin applied to the fibers is appropriately adjusted so that the resin does not significantly affect the electromagnetic shielding properties when the conductive fiber braid is connected to a ground terminal for grounding or when the conductive fiber braid is in contact with a drain line.

Further, if the coating resin is a thermoplastic adhesive resin, the adhesive resin can be melted by the heat of the sheath extruded on the surface of the knitted fabric when the sheath is extruded, and the sheath can be adhered to the knitted fabric by the melted resin to form the adhesive layer. Therefore, the step of molding the adhesive layer by extrusion molding of the adhesive resin can be omitted, and the step of molding the adhesive layer can be omitted when the sheath and the knitted fabric are to be bonded more firmly. In this case, since the coating resin on the insulating core wire side of the braided body is difficult to transfer heat during extrusion molding of the sheath material, the degree of adhesion between the braided body and the insulating core wire is very low, and the braided body peeling operation is not hindered.

Further, when the plurality of insulating core wires are twisted together with the interposed object or the pressure-sensitive adhesive tape is wound without using the interposed object so as to have a circular cross section, since a force (resistance against extrusion pressure) that presses from the core side over the entire circumference of the braid acts during extrusion molding of the adhesive resin and the sheath, a round adhesive layer having no unevenness is formed over the entire circumference of the outer surface of the braid, and the sheath is reliably adhered to the braid via the adhesive layer. Therefore, the braided body can be reliably peeled off when the sheath is peeled off.

Incidentally, in a mode in which a cross section of a core formed by twisting an insulating core wire has a spatial recess as in the shielded wire of patent document 3 (see patent document 3, fig. 1 and 2), if the shield layer is formed of a braided body, the braided body is highly flexible and enters the recess, and the outer periphery of the braided body is difficult to be round in cross section. Therefore, even when the adhesive resin or the sheath is extruded, the adhesive layer formed on the entire outer peripheral surface of the braid does not have a circular cross section and thus unevenness, and the adhesive strength between the braid and the sheath adhered via the adhesive layer is not preferable to the present invention in which the adhesive layer is formed in a circular shape having no unevenness over the entire outer surface of the braid.

As the conductor and the drain line of the insulated core wire, known soft copper twisted wires, soft copper element wires, and the like can be used, but for example, if the conductor and the drain line are formed of copper alloy twisted wires or element wires having the following structure and having excellent bending resistance, it is possible to maintain effective electromagnetic shielding characteristics for a long period of time even when the conductor and the drain line are repeatedly subjected to bending action.

Note the book

(Zr: 0.01 to 0.05 wt%, Cr: 0.01 to 0.05 wt%, or adding 0.002 to 0.3 wt% In total of at least one of In, Sn, Ag, Al, Bi, Ca, Fe, Ge, Hf, Mg, Mn, Ni, Pb, Sb, Si, Ti, Zn, B, Y and O, the remainder consisting essentially of Cu (see claim 2 of patent document 4))

The present invention is configured as described above, and therefore, can provide a shielded electric wire which is excellent in bending resistance and electromagnetic shielding properties and can be easily subjected to end processing.

Drawings

Fig. 1 is a sectional view of one embodiment of a shielded electric wire of the present invention.

Fig. 2 is a partially cut-away front view of a main part of the embodiment.

Fig. 3 is a perspective view for explaining the end processing of the embodiment.

Detailed Description

Fig. 1 and 2 show an embodiment of a shielded electric wire P according to the present invention, which is used for a robot cable and includes: the conductive wire comprises 8 twisted insulating core wires 1, an interposed object 2 between the insulating core wires 1, a pressure tape 3 wound (wound) in a transverse direction around the outer periphery of a core 1' composed of the insulating core wires 1 and the interposed object 2, a drain wire 4 extending over the entire length of the wire provided on the outer surface of the pressure tape 3, a conductive fiber braid 5 formed on the outer peripheral surface of the pressure tape 3 with the drain wire 4 interposed therebetween, a sheath (protective layer) 6 forming the outer peripheral surface of the braid 5, and an adhesive layer 7 between the braid 5 and the sheath 6.

The cross-sectional area of the insulated core wire 1 is 0.2mm²An insulating coating 1b such as polyvinyl chloride is provided on the copper alloy twisted wire 1 a. The number, outer diameter, and the like of the insulated core wires 1 can be set as appropriate according to the mode of use. In this embodiment, the insulating coating 1b of each of the insulated core wires 1 can be recognized as the insulating coating 1b made of polyvinyl chloride by appropriately making the insulating coating 1b of each of the insulated core wires 1 in different colors such as red, green, black, and white.

The sandwich 2 is made of cotton yarn, and is used to round the core 1' when the respective insulated core wires 1 are twisted, and a known sandwich such as PPC yarn other than cotton yarn can be suitably used. The core 1' is formed into a circular cross section as shown in fig. 1 by twisting the insulated core wire 1 with the interposed article 2 interposed therebetween.

The pressure-sensitive adhesive tape 3 is made of a paper tape or a plastic tape, and can be added in the longitudinal direction or wound in the transverse direction to maintain the circular cross-sectional shape of the core 1' made of the insulated core wire 1 and the sandwiched object 2, but in the present embodiment, it is wound in the transverse direction (winding).

The drain line 4 is formed of a cross-sectional area of 0.2mm²The copper alloy twisted wire of (1) may be added in the longitudinal direction or wound in the transverse direction, but in the present embodiment, it is one wound in the transverse direction. The number of which is arbitrary.

The conductive fiber woven body 5 is made of carbon fiber, copper-plated polyester fiber, or the like, and both are used (respective shield wires are manufactured) in the present embodiment, and are woven at a weaving density of 100%.

The sheath 6 is made of a known resin such as polyvinyl chloride, polyethylene, polyurethane, or polyester, and in the present embodiment, polyvinyl chloride is used.

As the adhesive layer 7, an adhesive layer having high adhesiveness to the knitted fabric 5 and the sheath 6 is suitably used, and in the present embodiment, a polyester-based thermoplastic adhesive resin is used. The adhesive layer 7 may be made of a thermoplastic adhesive resin such as polystyrene, vinyl acetate, polyethylene, polypropylene, polyamide, rubber, or acrylic. In addition, although an additive such as metal powder, carbon black, a filler, or a reinforcing material may be added to the adhesive agent layer 7, when an amount of the additive is added to a certain amount or more, the additive is easily exposed from the surface of the adhesive agent layer, and it is difficult to ensure good adhesion to the jacket 6, and therefore, the amount of the additive is appropriately selected in consideration of adhesion when the additive is added.

The shielded electric wire P of the present embodiment is configured as described above, and in the manufacturing thereof, first, the insulating core wire 1 and the interposed object 2 are fed into a twisting machine and twisted, the pressure tape 3 is transversely wound around the twisted core 1', and the drain wire 4 is transversely wound over the entire length of the electric wire, and then, the conductive fiber braid 5 is formed by using a braiding machine.

Next, an adhesive resin is extruded over the entire outer peripheral surface of the core 1' on which the conductive fiber woven body 5 is formed using an extruder to form an adhesive layer 7, and then the resin is extruded using the extruder to form a sheath 6, thereby manufacturing the shielded electric wire P of the present invention.

The shielded electric wire P thus manufactured can be applied to communication, power, and the like as a cable for a robot, and compared to a shielded electric wire using the above-described conventional braid, the braid 5 is integrated by being adhered to the sheath 6 when subjected to a bending action accompanying the operation of the robot, and therefore the structure of the braid 5 is less likely to collapse and is excellent in bending resistance.

In the end processing of the shielded electric wire P, first, as shown in fig. 3, a cut t is formed by scissors or wire stripper in a desired length portion of the end over the entire circumference of the sheath 6. The slits t are also formed in the braided body 5 to such an extent that the drain lines 4 are not cut (the slits t are not formed). At this time, the core 1' is formed to have a circular cross section, the adhesive layer 7 is formed on the entire outer peripheral surface thereof by extrusion molding of an adhesive resin, and the end braid 5' is reliably adhered (integrated) to the entire inner peripheral surface of the sheath 6' by the adhesive layer 7, so that the cut t can be easily formed in the braid 5' together with the sheath 6 '.

Next, when the jacket 6 'at the end is moved by wire stripper or the like as shown by the arrow in the figure from the state where the slit t is formed, the braided body 5' can be reliably peeled off together with the jacket 6 'at the end through the slit t, and the core 1' of the insulated core wire 1 around which the pressure tape 3 is wound and the drain wire 4 is transversely wound is exposed (from the state of the chain line to the state of the solid line in fig. 3).

After that, as in the conventional technique, the pressure-sensitive adhesive tape 3 and the drain line 4 are peeled off from the core 1' of the insulated core wire 1, and after an operation such as peeling off the insulating coating 1b of the insulated core wire 1, the insulated core wire 1 and the drain line 4 are connected to terminals of various connectors and electronic devices.

In the shielded wire P according to the above embodiment, the conductive fiber woven body 5 may be a conductive fiber woven body made of resin-coated fibers.

When the coating resin is a thermoplastic adhesive resin, the adhesive resin can be melted by the heat of the extruded sheath 6 when the sheath 6 is extruded, so that the sheath 6 adheres to the knitted fabric 5 and the adhesive layer 7 is formed. Therefore, the step of forming the adhesive layer 7 by extrusion molding of the adhesive resin can be omitted. Further, as the coating resin, a coating resin having high adhesiveness to the sheath 6 can be suitably used, and for example, a polyester-based thermoplastic adhesive resin or the like can be used as described above.

The conductor 1a and the drain line 4 of the insulated core wire 1 may be an aggregate twisted wire or a single wire of the copper alloy wire.

On the other hand, the drain line 4 can be omitted. In this embodiment, the conductive fiber braid 5 is used for grounding. Specifically, when the braided body 5 is peeled off, a part of the braided body 5 is left without being peeled off, and the left braided body 5 is connected to a ground terminal of an electronic device or the like. To explain the procedure in more detail, when the cuts t are formed on the outer peripheries of the sheath 6 and the knitted body 5 with scissors or the like, the cuts t are formed on the entire outer periphery of the sheath 6, and a part of the outer periphery of the knitted body 5 where no cut t is formed is left, and in this state, the sheath 6' is peeled off from the end by a required length. In this peeling, the jacket 6' is slowly peeled off so that the knitted fabric 5 of the portion where the slit t is not formed is not peeled off at the same time. Thus, since a part of the braid 5 remains on the product (wire body) side without following the sheath 6', the remaining braid 5 is connected to a ground terminal or the like of an electronic device or the like.

The pressure-sensitive adhesive tape 3 may be omitted as long as it does not interfere with the twisting of the insulated core wire 1. At this time, each of the insulated core wires 1 is twisted together with the sandwiched material 2, and the twisted core 1' is formed into a circular cross section.

The shield electric wire P of the present invention can be applied not only to a robot cable but also to other various cables requiring bending resistance.

The international application claims priority to japanese patent application No. 2014-.

As described above, the embodiments disclosed herein are not limited to the examples in all aspects. The scope of the present invention is defined by the claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Description of reference numerals: p … shielded electrical wire; t … cutting the sheath and the braided body; 1 … insulating the core wire; 1a … insulating the conductor of the core wire; 1b … insulating coating of the insulated core wire; 1' … a core formed by stranding insulated core wires; 2 … clamping objects; 3 … pressing the adhesive tape; 4 … drain line; 5 … conductive fiber braid; a 5' … stripped end braid; 6 … sheath (protective layer); 6' … stripped end sheath; 7 … adhesive layer.

Claims

1. A shielded electric wire (P) in which a plurality of insulating core wires (1) are twisted to form a core (1'), a conductive fiber braid (5) is formed on the outer periphery of the core (1'), and a sheath (6) is provided on the outer side of the conductive fiber braid (5),

a pressure tape (3) is provided on the outer periphery of a core (1') formed by twisting the plurality of insulated core wires (1) so that the cross section of the core (1') is circular,

an adhesive layer (7) is interposed between the conductive fiber woven body (5) and the sheath (6), the conductive fiber woven body (5) is adhered to the sheath (6) by the adhesive layer (7),

the adhesive layer (7) is formed on the entire outer peripheral surface of the conductive fiber woven body (5) by extrusion molding of a thermoplastic adhesive resin,

the conductive fiber woven body (5) is formed of conductive fibers coated with a resin.

2. The shielded electric wire according to claim 1,

a drain wire (4) is arranged between the pressing tape (3) and the conductive fiber woven body (5), and the drain wire (4) is electrically connected with the conductive fiber woven body (5).

3. The shielded electric wire according to claim 1 or 2,

the coated resin is used as a thermoplastic adhesive resin.

4. The shielded electric wire according to claim 1 or 2,

a plurality of insulated core wires (1) are twisted together with a clip (2) to make the core (1') have a circular cross section.

5. The shielded electric wire according to claim 3,